An official website of the United States government.
Here's how you know we're official.
A .gov website belongs to an official government organization in the United States.
A small lock or https:// means you’ve safely connected to a .gov website. Share sensitive information only on official, secure websites.
Tiny cells called zooxanthellae live within most types of coral polyps. They help the coral survive by providing it with food resulting from photosynthesis. In turn, the coral polyps provide the zooxanthellae with a protected environment and the nutrients they need to carry out photosynthesis.